In cases where sewage pipes or other pipelines that are buried underground have aged, methods for constructing a pipe lining, wherein a lining is applied to the inner circumferential surface to repair the pipeline without unearthing the pipeline, have already been proposed and are being employed in practical applications.
With the aforementioned methods for constructing a pipe lining, a pipe-lining material, which is formed, e.g., by impregnating a tube-shaped resin-adsorbent with an uncured thermosetting resin, is inserted into a pipeline via fluid pressure while being everted, and the impregnated thermosetting resin is cured by heating the pipe-lining material using an arbitrary method when the pipe-lining material is pressed against the inner circumferential wall of the pipeline by fluid pressure. A plastic pipe is thereby formed within the pipeline and the pipeline is repaired.
In another well-known method for repairing a pipeline using a rehabilitating pipe (Patent Document 1), a plastic material is used to integrally form a segment (block) comprised of an inner-surface plate constituting the inner circumferential surface and lateral plates and end plates that are vertically arranged on the rim of the inner-surface plate. Segments are linked in the circumferential direction to assemble pipe units (short pipes), which are themselves linked in the pipe length direction to make the rehabilitating pipe. This method is used for large-bore pipelines.
Patent Document 1: Japanese Laid-open Patent Application No. 2003-286742
Repairing pipeline facilities using a rehabilitating pipe that uses conventional segments has drawbacks in that only a minimal internal framework structure is provided in the circumferential direction, and deformation readily occurs due to external forces. It is proposed in Patent Document 1, for example, that a plurality of reinforcing bars be positioned in the circumferential direction to yield an internal framework structure (paragraph [0019]), but since the reinforcing bars are attached to the segments using an adhesive, or are connected and attached by binding cable to bolts for use in linking in the pipe length direction, problems have arisen in that the segments are not restrained with adequate force in the circumferential direction, and deformation occurs if major external forces act on the pipe unit and the rehabilitating pipe.